Your familiar acts independently of you, but it always obeys your commands. It rolls its own initiative and acts on its own turn. A familiar can't attack, but can take other actions as normal.
When the familiar drops to 0 hit points, it disappears. It reappears after you cast this spell again. While within 100 feet of you, you can communicate with it telepathically. As an action, you can see/hear through your familiar's eyes and ears (instead of your own) until the start of your next turn, gaining the benefits of any of its special senses.
As an action, you can temporarily dismiss your familiar. It disappears into a pocket dimension awaiting your summons. Or you may dismiss it forever. As an action while it is temporarily dismissed, you can cause it to reappear in any unoccupied space within 30 feet of you.
When you cast a touch spell, your familiar can deliver the spell as if it cast the spell. Your familiar must be within 100 feet of you, and uses its reaction to deliver the spell for you. If the spell requires an attack roll, you use your attack modifier for the roll.